BUdR is an agent which may make tumor tissue more receptive to treatment with radiation. This study will determine if the experimental drug BUdR given before and during radiation therapy, followed by the chemotherapy drugs procarbazine, CCNU, and vincristine can slow the growth of tumors. It will compare the efficacy of treatment with radiotherapy and PCV chemotherapy versus radiotherapy plus BUdR and PCV chemotherapy. The endpoints for this evaluation will be: Time to disease recurrence or progression, measured from the first day of treatment; Response rates and disease stabilization rates; Survival time, measured from the first day of treatment; and Activity level as determined by Karnofsky Performance Status.